Resistor with terminal mounting means



Aug. 19, 1969 1.. E. WEYENBERG RES ISTOR WITH TERMINAL MOUNTING MEANSFiled Sept. 27, 1967 m m E v m [MA/1g l. WIYFNBERG US. Cl. 317-101 7Claims ABSTRACT OF THE DISCLOSURE An electrical resistance apparatus iscombined with a circuit board. The resistor includes an insulating coreand a resistance wire is wound around the core, with the ends of theWire being connected to terminal strips which encircle the core. One endof each terminal strip projects through an opening in the board and isconnected to an electrical circuit which is located on the opposite sideof the board from the resistor. The other end of each terminal stripprojects laterally from the first end and bears against the surface ofthe board to space the resistor from the board. The lateral legs of theterminal strips project in opposite directions from the longitudinalcenterline of the resistor and serve to support the resistor from theboard and stabilize the resistor against vibration. As the resistor isspaced out of contact with the board, air can circulate around theresistor to thereby minimize heat concentration during operation.

In a printed circuit system, the electrical printed circuit is generallylocated on one side of an insulating board, and the various electricalcomponents are positioned on the opposite side of the board, with leadsextending through openings in the board and connecting the componentswith the printed circuit. Electrical resistors used in printed circuitsgenerate considerable heat and even though the resistor may be providedwith a ceramic coating, the heat generated by the resistor can range upto 300 to 400 C. above ambient temperature. Thus, if the resistor is incontact with the board, the high temperatures developed may melt ordecompose the board, or the intense heat can damage other electricalcomponents in the area. If the conventional resistor is spaced away fromthe board, a cooling effect is provided which reduces the excessive heatconcentration, but in this case the resistor is normally supported onlyby the electrical leads and in service, vibration tends to fracture theleads.

The present invention is directed to an improved resistor constructionfor use with a circuit board which reduces heat concentrations and yetenables the resistor to withstand vibration without fracture of theleads. According to the invention, the resistor includes an insulatingcore and a resistance wire is wound around the core, with the ends ofthe wire being connected to terminal strips which encircle the core. Oneend or leg of each terminal strip projects through an opening in theboard and is connected to the electrical circuit located on the oppositeside of the board from the resistor.

The other end or leg of each terminal strip projects diagonally orlaterally from the first end and bears against the surface of the boardto space the resistor from the board. The lateral legs of the terminalstrips project in opposite directions from the longitudinal centerlineof the resistor and thereby serve to support the resistor from theboard, as well as stabilizing the resistor against vibration. As theresistor is spaced from the board, air is free to circulate around theresistor which eliminates intense concentrations of heat and preventsmelting or decomposition of the board, as well as damage to otherelectrical components in the area.

As the projecting legs are an integral part of the ter- United StatesPatent M 3,462,651 Patented Aug. 19, 1969 ice minal strip, only a singleweld is required to assemble the terminal strips with the insulatingcore, and this reduces the cost of manufacture of the resistor overconventional types.

The legs of the terminal strips are generally rectangular in crosssection, and this increases the resistance of the legs to fracture andalso enables wire to be more easily wrapped around the end of theprojecting leg to join the leg to the electrical circuit.

Other objects and advantages will appear in the course of the followingdescription.

The drawings illustrate the best mode presently contemplated of carryingout the invention.

In the drawing:

FIG. 1 is a fragmentary plan view of a printed circuit board;

FIG. 2 is a perspective view of the resistor of the invention asconnected to the printed circuit board; and

FIG. 3 is an end view of the resistor as connected to the board.

The drawings illustrate a printed circuit board 1 having a printedcircuit 2 on one surface, and a resistor 3 is located on the oppositesurface and is connected to the printed circuit 2.

The board 1 is formed of an electrically insulating material such asplastic, or the like, and any conventional insulating material used inprinted circuits can be employed. The printed circuit 2, in itself,forms no part of the invention and can take any desired form. While thedrawings illustrate a printed circuit 2, the invention is equallyapplicable to the use of wire lead circuits in place of the printedcircuit 2.

The resistor 3 includes a central insulating core 4 and a resistancewire 5 is wound around the core. Each end of the wire 5 is connected toa terminal strip 6 located at opposite ends of the core 4. In mostcases, a ceramic coating 7 is applied to the outer surface of theresistor and covers the wire 5, as well as the terminal strips 6.

According to the invention, each terminal strip 6 includes a circularsection 8, which encircles the core 4, and central sections 9 extendoutwardly from the ends of the circular section 7. The central sections9 are disposed flatwise and are connected together by a weld 10 tofirmly secure the terminal strip 6 to the core.

Formed integrally with one of the central sections 9 is a leg 11 "whichextends through an opening 01' slot 12 in the board 1 and is connectedto the printed circuit 2 by a solder connection 13. It is contemplatedthat the leg 11 can be connected to the printed circuit by any desiredmeans, such as wire wrapping or the like, which will provide thenecessary electrical connection between the leg 11 and the printedcircuit 2.

A laterally extending leg 14 is formed integrally with the other of thesections 9 and the outer end of the leg 14 bears against the surface ofthe board 1. As best shown in FIG. 2, the lateral legs 14 of eachterminal strip 6 extend in opposite directions from the longitudinalcenterline of the resistor. While the drawings show the legs 14 to begenerally straight and disposed generally normal to the legs 11, it iscontemplated that the legs 14 can extend diagonally or can take othershapes or configurations as long as a portion of the leg 14 bearsagainst the board 1 at a location spaced laterally from the opening 12.

The legs 14 serve to space the resistor from the surface of the board 1and thereby permit air to circulate around the entire periphery of theresistor. By providing circulation of air around the resistor, excessiveconcentrations of heat at the board 1 are eliminated and this preventsmelting or decomposition of the board and also eliminates any danger ofoverheating of the other electrical components in the area.

As the legs 14 extend on opposite sides of the longitudinal centerlineof the resistor, the legs act to stabilize the resistor againstvibration and shock, and thereby tend to minimize the possibility offracture of the legs 11 which are connected to the printed circuit 2.

As the leg 11 and the supporting leg 14 are an integral part of theterminal strip 6, the manufacture is simplified in that only a singlepart is required. Moreover, the entire unit can be readily assembled bymerely welding or otherwise connecting the ends of the resistance wire 5to the terminal strips 6 and then connecting the central sections 9 bymeans of the weld 10. Thus, the manufacture and assembly of the resistoris considerably simplified over that of the conventional resistor.

The rectangular configuration of legs 11 aids in wire wrapping of theleads to the printed circuit. Moreover, the rectangular legs 11 arestiffer than conventional wire leads and this enables the legs to beinserted into the holes in the board without binding.

Various modes of carrying out the invention are contemplated as beingwithin the scope of the following claims particularly pointing out anddistinctly claiming the subject matter which is regarded as theinvention.

I claim:

1. In a resistance apparatus, a central insulating core, a resistancewire wound around the core, and a pair of terminal strips connected tothe wire, each terminal strip having a greater Width than thickness andincluding a body section encircling the core, each terminal strip alsoincluding a pair of central sections located at the ends of said bodysection and disposed flatwise with relation to each other, and eachterminal strip including an end section extending from each centralsection, one of said end sections of each terminal strip extendinggenerally radially with respect to said core and the second end sectionterminating short of the first end section and extending at an angle tosaid first end section, the second end section of one terminal stripextending in the opposite direction from the second end section of theother terminal strip.

2. The apparatus of claim 1, wherein said second end section extends atan angle of approximately 90 with respect to said first end section.

3. In an electrical apparatus, a support having a pair of opposedsurfaces, an electrical circuit disposed on a first of said surfaces,said support having a pair of openings therein, an electrical componentmounted on the second of said surfaces and having a pair of terminalstrips with each strip including -a first leg extending through one ofsaid openings and connected to the electrical circuit and including asecond leg disposed at a angle to the first leg and disposed generallyflatwise with respect to said second surface, said second leg of oneterminal strip extening in the opposite direction from the second leg ofthe other terminal strip, said second legs serving to space theelectrical component from said second surface and to stabilize thecomponent against vibration and shock.

4. The apparatus of claim 3, wherein said electrical component is aresistor comprising an insulating core and a resistance wire woundaround the core and connected to said terminal strip.

5. The apparatus of claim 3, wherein said terminal strip includes anannular section disposed around the core and a pair of central sectionslocated at the ends of the annular section and disposed fiatwise withrespect to each other, said first leg being connected to one of saidcentral sections and said second leg being connected to the other ofsaid central sections.

6. The apparatus of claim 5, and including means for securing thecentral sections together.

7. The resistor of claim 1, and including means for connecting saidcentral sections together.

References Cited UNITED STATES PATENTS 7,420 6/1850 Smith 336-1921,554,728 9/1925 Horle 336-208 1,932,923 10/1933 Bullinger 338-329 X2,636,963 4/1953 Wakefield 338-329 X 2,912,481 11/1959 Backus 336-1923,229,238 1/1966 Ellin 338-329 OTHER REFERENCES German printedapplication S.N. 1,137,090 to Rosenthal, published, Sept. 27, 1962.

ELLIOT A. GOLDBERG, Primary Examiner US. Cl. X.R.

